Carrot and beet juice together gives your body phosphorous/sulfur and potassium in a high dose. Vitamin A is also very rich in this mix. All of this equates one of the best natural builder of blood cells - especially the red blood corpuscles.
Peeling the beet is not required but it makes the juice a bit sweeter. Make sure to wash your root veggies well, unless you like eating dirt.
Caution: drinking too much beet juice at one time may cause a cleansing effect of the liver. This can actually cause you to become dizzy. So use plenty of carrots in your juice for balance. Also, beet juice will stain anything it touches including your skin - so pay attention to what you are wearing.